The integral is: ∮(x+y)/(x? +y？ )dx + (y-x)/(x？ +y？ )dy

Because the functions p and q are undefined at the origin, Green's formula cannot be directly used in this problem. If you need someone to help you calculate, you must give an integral curve. If the integral curve is a circle with the origin as the center, it is very simple. If not, it will be more troublesome.